A Brief Introduction To Marine Grade Metals

A Brief Introduction To Marine Grade Metals

  • 23 Dec 0

While the festive season is a time to wind down, relax with family and friends, and perhaps plan for the coming year ahead, it’s also the height of the summer for Australians. What better way to escape the heat than to head for the water. From swimming to fishing, water-based activities are the staple activity of the summer months. While water may be great for you, the same can’t be said for metals. Because of the corrosive effects that sea water has, any metals that are exposed to it for long periods of time can become damaged or weakened. For this reason, marine grade metals offer the perfect solution.

So what exactly are they?

Collectively marine based metals are specifically treated to withstand long lengths of time in water. Anything from brass, bronze, copper, and stainless or carbon steel can be utilised and will have a marine grade or type. This is usually but not always signified by a group of numbers or letters. In the case of stainless steel the marine grading is ‘T’ or ‘type 316’, but just to confuse you, in the case of materials such as brass, it’s usually referred to as ‘naval brass’.

To be able to withstand underwater or wet environments, specialised alloy elements are added including manganese, sulphur, chromium, nickel and molybdenum. One of the most popular forms of marine based metal is stainless steel.

T316 Marine Grade Steel

Type 316 stainless steel is by far the most widely used application for marine based products including boat propeller shafts, marine fittings, deck components, and storage vessels. Although not completely rust proof, it is highly effective at resisting corrosion and pitting when exposed to saline solutions because it has a high level of molybdenum. But not only that, it also has excellent resistance to liquids such as acid and other highly corrosive materials. For this reason it’s also used heavily in the chemical, petrochemical, and power transmission industries in a variety of guises. In addition stainless steel is a great insulator and therefore it’s also used for water bottles and flasks where retaining heat is important.

To make matters more complicated there are a wide variety of non-standard marine grade steels available which are used for specific purposes. For example, T316LS is a high purity version that is specifically used in the making of surgical tools. 316H has a higher carbon content giving it a greater rupture strength at high temperatures. As such it’s often used in the production of industrial boilers. Then there’s 316TI which has a high concentration of titanium. As titanium is biocompatible (e.g. it’s not harmful or toxic to living tissue) it’s ideal for surgical implants.

So there you have it, a brief, but hopefully interesting introduction to marine grade metals. If you have a water-based project and aren’t sure exactly what grade of metal you should be using then talk to the experts at Metro Steel. We’ve been fabricating and producing steel products, parts, and machinery for over 20 years, so I guess you could say we know our T316’s from our T304’s. Contact us on 07 3204 1000 for assistance.


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